Tanning agents



Patented Nov. 15 19 UNITED STATES PATENT OFFICE 2,136,997

TANNINGAGENTS Werner Asch,

Heinrich Jam, and Walter Pens on-the-Main-Hochst,

G. for

No Drawing. Application Farbenlndustrie Germany, assignorc to I.

Aktiengesellschaft, Frankt-on-the-Main, Germany rial No. 125,154. 1936 process of 8 Claims.

to tanning agents. No. 123,734, filed Arthur Voss, Walter Pense, Werner Asch entitled Tanpreparing them preparing water soluble derivatives which comprises d phenols or the obtainable by heating such mixtures with sulfonating agents and eliminating the sulfonation products hering electrolytes. sulfonic acids which to a far extent from the ad- By this process these resinas such are very sensitive to electrolytes and therefore are not very suitable as tanning agents. electrolytes but under agents become industri valuable tanning It is possible completely to remove the al conditions this is very dimcult. 0n the other hand, if all the electrolytes are not removed, there is a certain difllculty in dissolving the product and that is sometimes detrimental.

We have found to electrolytes still mixing the products tures of resins and thereof with that a profound insensibility present may be attained by obtained by sulfonating mixphenolic bodies or the esters synthetically prepared tanning agents. As such tanning agents there may especially be mentioned all sulfo pounds of high molecular we linking several aromatic nuclei,

acids of condensation nic acids of comight obtained by i. e. the sulfonic products obtained from aromatic bodies (phenols, naphthalene, aniline etc.) and bridge-forming agents, such as aldehydes, sulfur, sulfur chloride. sulfo group may be introduced In this case the either directly or by esteriflcation, peptisation etc.

In combination with the products described in the copending application mentioned above the known synthetic tanning agents are far less sensitive to the action of electrolytes. Furthermore the properties of these new mixtures may be varied to a greater extent than those of the known synthetic tanning agents. The mixtures may,

therefore, be

successfully applied in far more tanning processes of various kind than the known synthetic tanning agents.

The following examples serve to illustrate the invention, but they are not intended thereto; the parts are by weight:-

to limit it (1) parts of a resin-sulfonation product obtainable from pine resin and phenol prepared according to the afore-named Serial No. 123,734 are water at a temperature of 50 is mixed with 100 parts of a t U. S. application dissolved in 200 parts of C. The solution anning agent ob- February 10, 1937, Se- Germany Fcbrnary 14,

tained by sulfonating 81.5 parts of alpha-methyl naphthalene with parts of sulfuric acid (of 100 per cent. strength) and by peptizing into this solution 70 parts of a liquid resin made by alkaline condensation of two mols of phenol with 1 mol of paraformaldehyde. The solution is stirred at 50 C. untilit has completely become homogeneous and is brought to a pH-value of nearly 3 by the addition of caustic soda solution. Thereby the sensitivity to salt of the solution is diminished to a great extent. Calf pelts are tanned with this combination by treating them in a pit with liquors beginning with a strength of 05 B. A leather is thus obtained showing a light color and having smooth grains and a very good stretch. Y

(2) 400 parts of resinic ican colophony with tricresol are sulfonated with fuming sulfuric acid of 10 per cent. strength; as described in U. S. application Serial No. 123,- 734 the mixture is freed from electrolytes by washing it out, drying and grinding it. 200 parts of this powder are gradually added to 500 parts of a solution of tanning agents of 25 per cent. strength preparedsimilarly to Example 1--by peptizing a phenol-formaldehyde resin into butylnaphthalene sulfonic acid. With this tanning agent cow pelts strength of the liquors begins with 1 B. and is increased during the tannage upto 5B.

(3) parts of the resin-sulfonlc acid prepared according to Example 5 of U. S. application Serial No. 123,734 from 120 parts of liquid Swedish resin and 46 parts of beta-naphthol are dissolved in 200 parts of water and the solution is rendered distinctly acid with formic acid. 50 parts of a synthetic tanning sulfonic acid obtained by causing formaldehyde to react upon naphthalene sulfonic acid are stirred into the solution. The homogeneous solution is evaporated so as to form a dry substance which is pulverized. A mixture of, for instance, 50 parts of quebracho (soluble in the cold state, solid) and 50 parts of the powdered tanning a ent described above is dissolved in water so as to form a liquor of a strength of 10 B. In this liquor cow pelts are tanned which already have been tanned through in the color pits. When being treated with this combination the leather obtained is of lighter color and a better. stretch and is more plump than that treated with quebracho alone.

We claim:

1. A tanning agent consisting of the sulfonation product from a mixture of a phenolic body are tanned in a drum. The,

and a natural resin and having a content of an electrolyte not higher than 10 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

2. A tanning agent consisting of the sulfonation product from phenolic bodies and natural resins, esteriiied in the presence of catalysts, with a content of electrolyte not higher than 10 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

3. A tanning agent consisting of the sulfonation product from a mixture'of colophony and phenol and having a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation prodnets.

4. A tanning agent consisting of the sulfonation product from equimolecular proportions of colophony and phenol with a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

5. A tanning agent consisting of the sulionation product from colophony and cresol and having a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

6. A tanning agent consisting of the sulfonation product from equimolecular proportions of colophony and cresol and having a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

'7. A tanning agent consisting of the sulfonation product from colophony and xylenol and having a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclear aromatic condensation products.

8. A tanning agent consisting of the sulfonation product from equimolecular proportions of colophony and xylenol with a content of electrolyte not higher than 10 per cent., calculated upon a tanning agent of 100 per cent., mixed with synthetic tanning agents of the group consisting of water soluble polynuclea aromatic condensation products. it

WERNER ASCH. HEINRICH JANZ. WALTER PENSE. ARTHUR VOSS. 

